18122409 has 24 divisors (see below), whose sum is σ = 27799200. Its totient is φ = 11344320.

The previous prime is 18122399. The next prime is 18122431. The reversal of 18122409 is 90422181.

It is not a de Polignac number, because 18122409 - 2¹⁹ = 17598121 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18122309) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21997 + ... + 22805.

It is an arithmetic number, because the mean of its divisors is an integer number (1158300).

Almost surely, 2^18122409 is an apocalyptic number.

18122409 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

18122409 is a deficient number, since it is larger than the sum of its proper divisors (9676791).

18122409 is a wasteful number, since it uses less digits than its factorization.

18122409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 965 (or 962 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 18122409 is about 4257.0422830881. The cubic root of 18122409 is about 262.6668762041. Note that the first 3 decimals are identical.

The spelling of 18122409 in words is "eighteen million, one hundred twenty-two thousand, four hundred nine".